US20200261970A1

US20200261970A1 - Device and method for continuously removing impurities from molten metal

Info

Publication number: US20200261970A1
Application number: US16/865,530
Authority: US
Inventors: Kenzo Takahashi
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-11-15
Filing date: 2020-05-04
Publication date: 2020-08-20
Also published as: EP3711878A4; EP3711878A1; WO2019097799A1; AU2018368019A1; CA3081826A1; JP2019089112A; JP6526769B1

Abstract

A device for continuously removing impurities from molten metal includes a molten metal flow path body, an inlet-side closed end plate and an outlet-side closed end plate are provided in the molten metal flow path body so as to form an impurity removal space, an electrode device composed of an inlet-side electrode and an outlet-side electrode that face each other in a longitudinal direction of the molten metal flow path body, a magnetic field device composed of a pair of permanent magnets that face each other in a width direction, sandwich the impurity removal space, and an urging device composed of the electrode device and the magnetic field device applies a Lorentz force downward to molten metal in the impurity removal space so as to increase a density of the molten metal and cause impurities in the molten metal to rise up to a surface of the molten metal.

Description

TECHNICAL FIELD

The present invention relates to a device and a method for continuously removing impurities from molten metal.

BACKGROUND ART

Conventionally, productization from molten metal having electrical conductivity (conductivity), that is, non-ferrous molten metal (e.g., Al, Cu, Zn, or Si, alloy including at least two of these, Mg alloy, or the like) or molten metal other than non-ferrous molten metal includes, for example, steps of dissolving raw materials, adjusting components, removing impurities mixed in molten metal, and molding. Removal of impurities is generally referred to as purification of molten metal, and, for example, a ceramic filter is used therefor.
However, since an impurity removal method using a filter is, of course, a filtration method, clogging is likely to occur. Therefore, there is a problem such that the workability is deteriorated and the running cost is increased.
In other words, in a case of a filter type, how large the mesh is set to is actually an important point. In order to remove not only large impurities but also fine impurities, the mesh must be fine. However, if the mesh is made fine, clogging is more likely to occur. For example, clogging may occur instantaneously, and production may stop.
Thus, conventionally, flux is previously introduced into the molten metal prior to removal with a filter. By such introduction, impurities are changed into substances having a large particle size. As a result, it becomes possible to remove impurities while keeping the mesh large to some extent, and it is possible to increase the removal efficiency (trap efficiency) of the filter. However, it is not preferable to introduce flux into the molten metal in terms of product quality in many cases.

SUMMARY OF INVENTION

Technical Problem

As described above, according to a conventional method, it is actually impossible to continuously produce products without stopping production of products while removing impurities, including fine impurities, from molten metal.
The present invention has been made in view of such circumstances, and it is an object thereof to provide a device and a method for continuously removing impurities for enabling continuous manufacture of products while removing impurities from non-ferrous metal or other molten metal containing impurities with high accuracy.

Solution to Problem

An embodiment of the present invention is
a device for continuously removing impurities from molten metal, which sends electrically conductive molten metal to a metal product manufacturing device in a next stage, the device including:
a molten metal flow path body having a molten metal flow path for flowing electrically conductive molten metal that has flown from outside toward the metal product manufacturing device;
an inlet-side closed end plate and an outlet-side closed end plate that are provided in the molten metal flow path body so as to partition a front and a rear of the molten metal flow path and form an impurity removal space;
an electrode device composed of an inlet-side electrode and an outlet-side electrode that are provided in the impurity removal space, face each other in a longitudinal direction in which molten metal flows, and can be put into electrical contact with molten metal in the impurity removal space; and
a magnetic field device composed of a pair of permanent magnets that are provided outside the molten metal flow path forming body, face each other in a width direction intersecting the longitudinal direction, sandwich the impurity removal space of the molten metal flow path forming body in the width direction, have opposite poles facing each other, and can form a magnetic field in molten metal in the impurity removal space,
in which the electrode device and the magnetic field device constitute an urging device that can apply a Lorentz force downward to molten metal in the impurity removal space so as to increase a density of the molten metal and cause impurities in the molten metal to rise up to a surface of the molten metal.
Furthermore, an embodiment of the present invention is
a continuous impurity removal method for removing impurities from molten metal in sending electrically conductive molten metal to a metal product manufacturing device in a next stage, the method including:
preparing a molten metal flow path body having a molten metal flow path for flowing electrically conductive molten metal that has flown from outside toward the metal product manufacturing device;
providing an inlet-side closed end plate and an outlet-side closed end plate in the molten metal flow path body so as to partition a front and a rear of the molten metal flow path and form an impurity removal space;
providing, in the impurity removal space, an electrode device composed of an inlet-side electrode and an outlet-side electrode that face each other in a longitudinal direction in which molten metal flows and can be put into electrical contact with molten metal in the impurity removal space;
providing, outside the molten metal flow path forming body, a magnetic field device composed of a pair of permanent magnets that face each other in a width direction intersecting the longitudinal direction, sandwich the impurity removal space of the molten metal flow path forming body in the width direction, have opposite poles facing each other, and can form a magnetic field in molten metal in the impurity removal space; and
causing an urging device composed of the electrode device and the magnetic field device to apply a Lorentz force downward to molten metal in the impurity removal space so as to increase a density of the molten metal and cause impurities in the molten metal to rise up to a surface of the molten metal.
Furthermore, an embodiment of the present invention is
a device for continuously removing impurities from molten metal, which sends electrically conductive molten metal to a metal product manufacturing device in a next stage, the device including:
a molten metal flow path body having a molten metal flow path for flowing electrically conductive molten metal that has flown from outside toward the metal product manufacturing device;
an inlet-side closed end plate and an outlet-side closed end plate that are provided in the molten metal flow path body so as to partition a front and a rear of the molten metal flow path and form an impurity removal space;
an electrode device composed of an inlet-side electrode and an outlet-side electrode that are provided in the impurity removal space, face each other in a longitudinal direction in which molten metal flows, and can be put into electrical contact with molten metal in the impurity removal space; and
a magnetic field device composed of a pair of permanent magnets that are provided outside the molten metal flow path forming body, face each other in a width direction intersecting the longitudinal direction, sandwich the impurity removal space of the molten metal flow path forming body in the width direction, have opposite poles facing each other, and can form a magnetic field in molten metal in the impurity removal space,
in which the outlet-side electrode is provided in a floating state in the impurity removal space so that a first gap opened vertically is formed between the outlet-side electrode and a bottom surface of the molten metal flow path forming body and a second gap opened in the longitudinal direction is formed between the outlet-side electrode and the outlet-side closed end plate, and
the electrode device and the magnetic field device constitute an urging device that can apply a Lorentz force downward to molten metal in the impurity removal space so as to increase a density of the molten metal and cause impurities in the molten metal to rise up to a surface of the molten metal, and can send molten metal on an inner side than the outlet-side electrode in the impurity removal space through the first gap to the second gap.
Furthermore, an embodiment of the present invention is
a continuous impurity removal method for removing impurities from molten metal in sending electrically conductive molten metal to a metal product manufacturing device in a next stage, the method including:
preparing a molten metal flow path body having a molten metal flow path for flowing electrically conductive molten metal that has flown from outside toward the metal product manufacturing device;
providing an inlet-side closed end plate and an outlet-side closed end plate in the molten metal flow path body so as to partition a front and a rear of the molten metal flow path and form an impurity removal space;
providing, in the impurity removal space, an electrode device composed of an inlet-side electrode and an outlet-side electrode that face each other in a longitudinal direction in which molten metal flows and can be put into electrical contact with molten metal in the impurity removal space;
providing, outside the molten metal flow path forming body, a magnetic field device composed of a pair of permanent magnets that face each other in a width direction intersecting the longitudinal direction, sandwich the impurity removal space of the molten metal flow path forming body in the width direction, have opposite poles facing each other, and can form a magnetic field in molten metal in the impurity removal space;
providing the outlet-side electrode in a floating state in the impurity removal space so that a first gap opened vertically is formed between the outlet-side electrode and a bottom surface of the molten metal flow path forming body and a second gap opened in the longitudinal direction is formed between the outlet-side electrode and the outlet-side closed end plate; and
causing an urging device composed of the electrode device and the magnetic field device to apply a Lorentz force downward to molten metal in the impurity removal space so as to increase a density of the molten metal and cause impurities in the molten metal to rise up to a surface of the molten metal, and send molten metal on an inner side than the outlet-side electrode through the first gap to the second gap.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory plan view illustrating the overall configuration of a device for continuously removing impurities from molten metal according to an embodiment of the present invention.

FIG. 2 is an explanatory sectional view taken along line II-II of FIG. 1.

FIG. 3 is an explanatory sectional view taken along line III-III of FIG. 2.

FIG. 4 is an explanatory sectional view taken along line IV-IV of FIG. 2.

FIG. 5 is an explanatory view illustrating a usage state corresponding to a part of FIG. 2.

FIG. 6 is an explanatory view for explaining generation of a Lorentz force.

FIG. 7a is an explanatory view for explaining a pressure state in molten metal.

FIG. 7b is an explanatory view for explaining a pressure state in molten metal.

FIG. 8 is an explanatory partial view illustrating a modified example corresponding to FIG. 5.

FIG. 9a is an explanatory longitudinal sectional view illustrating a specific example of an outlet-side closed end plate.

FIG. 9b is an explanatory longitudinal sectional view illustrating a specific example of an outlet-side closed end plate.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory plan view illustrating the entire configuration of an embodiment of a device 100 for continuously removing impurities from molten metal according to the present invention. The metal is a non-ferrous metal having electrical conductivity or another metal. The non-ferrous metal or another metal is a non-ferrous metal of a conductor (electric conductor) such as Al, Cu, Zn, an alloy including at least two of these, or an Mg alloy, or a metal other than the non-ferrous metal.
In FIG. 1, the flow of molten metal M is indicated by a solid arrow AR1, and the movement of impurities IM is indicated by a broken arrow AR2. That is, it is shown that the impurities IM are removed laterally while the molten metal M is flowing along the arrow AR1.
More specifically, FIG. 1 illustrates a case where a tilting type melting furnace is used as an example. As can be seen from FIG. 1, the impurity removing device 100 receives molten metal M from a melting furnace 200 in the preceding stage, allows the molten metal M flow inside the impurity removing device 100, causes impurities in the molten metal M to positively rise up to the vicinity of the liquid surface during the molten metal M is flowing so that the impurities can be removed by arbitral means, and causes the molten metal M to flow into a mold 300 in the following stage after impurities are removed, so that a product (ingot) such as a billet or a slab, for example, can be manufactured from high-quality molten metal M. A general-purpose melting furnace 200 and a general-purpose mold 300 can be employed. Therefore, for example, the impurity removing device 100 of the present invention can be additionally provided to an existing melting furnace 200 and an existing mold 300 later.
The melting furnace 200 is a general-purpose tilting type melting furnace as described above. That is, the melting furnace 200 includes a container-shaped melting furnace main body 1 having an opening 2 at the top. A spout 3 for the molten metal M is formed at a side wall on the front side (left side in the figure) of the tilting type melting furnace main body 1. A general-purpose gas burner 4 is attached to a rear side wall. The raw material of the electrically conductive metal introduced from the opening 2 is heated by the gas burner 4 to be molten metal M and is housed in the melting furnace main body 1.
FIG. 2 is an explanatory longitudinal sectional view taken along line II-II of FIG. 1. As can be seen from FIG. 2, a hinge mechanism 6 is provided at an outer bottom portion of the melting furnace main body 1 so as to be able to derrick and rotate. As a result, it is configured to be able to derrick and rotate on a horizontal shaft 6 a from an upright state to an inclined pouring state. This melting furnace main body 1 can adjust the amount of molten metal supplied to a gutter main body 10. The molten metal M is poured from the spout 3 to the impurity removing device 100 in the next stage by tilting the melting furnace main body 1. This state is illustrated in FIG. 5. By adjusting the angle at which the melting furnace main body 1 is inclined, the head h illustrated in FIG. 2 is changed, and the flow rate of the molten metal M from the melting furnace main body 1 to the gutter main body 10 can be changed. It is to be noted that the level of the molten metal M in the gutter main body 10 is performed by changing the height of an outlet-side closed end plate 11. Moreover, as illustrated in FIG. 8, one electrode 13 b, which will be described later, can be provided separately from the inlet-side closed end plate 8. The flow of the molten metal M at this time is as illustrated in FIG. 8.
The impurity removing device 100 that receives the molten metal M from the melting furnace 200 is configured to have a function as a so-called gutter that allows the received molten metal M flow from right to left in FIG. 1 and give the molten metal M to the mold 300 in the next stage, and a selective accumulation function of selectively accumulating impurities in the molten metal M that are caused to rise up to the vicinity of the liquid surface during the flow.
That is, as can be seen particularly from FIG. 2, the impurity removing device 100 includes the gutter main body (sorting tank) (molten metal flow path body) 10, and a magnetic field device 12 that sandwiches the gutter main body 10 in the width direction. Furthermore, as can be seen particularly from FIG. 1, the impurity removing device 100 has an electrode device 13 composed of a pair of electrodes 13 a and 13 b that are housed inside the gutter main body 10 (molten metal flow path) and face each other. The magnetic field device 12 and the electrode device 13 constitute an urging device 30 that applies a Lorentz force f downward to the molten metal M, as will be described later in detail.
As can be seen from FIG. 1, the gutter main body 10 is configured to guide the molten metal M from the melting furnace 200 to the mold 300, and the gutter main body 10 is made of a refractory material and has a substantially U-shaped cross section as can be seen from FIG. 3. The gutter main body 10 can be installed with a gradient so that the left side becomes lower than the right side in FIG. 2 in order to make the flow of the molten metal M smooth.
As can be seen from FIG. 2, the gutter main body 10 has an inflow auxiliary plate 7A that receives the molten metal M from the melting furnace 200, and an inlet-side closed end plate 8, a main flow path bottom plate 9, and the outlet-side closed end plate 11 that follow. Furthermore, there are right and left side plates 15 a and 15 b sandwiching these members in the width direction. The right and left side plates 15 a and 15 b, the inlet-side closed end plate 8, and the outlet-side closed end plate 11 form a main flow path (impurity removal space) 14 as an impurity removal portion.
The outlet-side closed end plate 11 can be configured such that the height thereof can be adjusted. Arbitral configuration configured such that the height thereof can be adjusted can be employed. For example, as can be seen from FIGS. 9a and 9b , the outlet-side closed end plate 11 may be composed of a main body 11 a and an auxiliary plate 11 b which are bolted to each other, and the auxiliary plate 11 b may be vertically shifted with respect to the main body 11 a.
The inlet-side electrode 13 a in the electrode device 13 is provided in close contact with the inlet-side closed end plate 8, and the outlet-side electrode 13 b is spaced from the outlet-side closed end plate 11 with a gap (second gap) G2 in the longitudinal direction and is provided in a floating state of floating with a gap (first gap) G1 in the depth direction. As a result, the molten metal M flows through the gaps G1 and G2, flows over the outlet-side closed end plate 11, or so-called overflows, and flows out from the main flow path 8 through an outflow auxiliary plate 7B toward the mold 300 as will be described later.
A power supply 16 is connected between the pair of electrodes 13 a and 13 b in the electrode device 13. This power supply 16 is configured to be able to pass an alternating current as well as a direct current. Furthermore, it is configured to switch the polarity of a direct current.
The magnetic field device 12 is provided on both right and left sides of the gutter main body 10 as can be seen from FIGS. 1 and 4. This magnetic field device 12 includes a pair of right and left permanent magnets 12 a and 12 b, and the gutter main body 10 is sandwiched between the pair of permanent magnets 12 a and 12 b. The pair of permanent magnets 12 a and 12 b have opposite poles facing each other, and in this embodiment, the inner sides of the pair of permanent magnets 12 a and 12 b are magnetized respectively to an S pole and an N pole. As a result, the lines of magnetic force ML from an upper permanent magnet 12 b in FIG. 4 penetrate the molten metal M in the gutter main body 10 and reach a lower permanent magnet 12 a. Thus, in actual use, a current I flows between the pair of electrodes 13 a and 13 b as can be seen from FIG. 4. Therefore, the lines of magnetic force ML and the current I intersect each other. As a result, a Lorentz force f to push the molten metal M downward is generated in the molten metal M as illustrated in FIG. 6. It is to be noted that the magnetic field device 12 can be constituted of an electromagnet.
Next, the operation of the embodiment of the present invention will be described.
As can be seen from FIGS. 1 and 2, when electrically conductive metal is introduced into the melting furnace 200 and is heated and molten, the molten metal M is caused to flow from the melting furnace 200 into the main flow path 14 by increase of the molten metal M and the tilt illustrated in FIG. 5.
In this main flow path 14, the lines of magnetic force ML and the current I intersect each other as can be seen from FIG. 4. This concept is illustrated in FIG. 6 described above. As a result, a Lorentz force f is generated and acts on the molten metal M as a force in a direction to push the molten metal M downward. As a result, the pressure inside the molten metal M increases as it goes from the surface to a bottom portion. The state of pressure distribution in this case is illustrated in FIG. 7a . That is, the density of the molten metal M becomes larger toward the bottom portion due to the gravity in addition to the Lorentz force f. This density affects greatly the buoyancy of impurities IM contained in the molten metal M. That is, when the density is high, a large buoyancy acts on impurities IM.
Therefore, in a state in which the Lorentz force f is generated, impurities IM in the molten metal M rise in the molten metal M and reach the liquid level. That is, impurities IM tend to settle in the molten metal M by its own weight. Moreover, a buoyancy due to the molten metal M acts on impurities IM. Thus, when the density of the molten metal M increases, a large buoyancy acts on impurities IM in the molten metal M. Therefore, impurities IM rise or fall according to a difference between the buoyancy and the settlement force. Thus, by setting the Lorentz force f to an expected value, the buoyancy becomes larger than the settlement force, and impurities IM rise in the molten metal M and reach the vicinity of the liquid surface. This operation is continuously performed in the process of flow of the molten metal M through the main flow path 14.
In this way, impurities IM rise up to the vicinity of the surface of the molten metal M. Impurities IM that have risen up are automatically or artificially discharged to an impurity receiver 40 via the impurity removing plate 7C as can be seen from FIG. 3 by arbitral means. As illustrated in FIG. 3, the impurity removing plate 7C has a mountain-shaped cross section.
Moreover, in the gutter main body 10, the molten metal M is pushed down by application of pressure as illustrated in FIG. 7b as described above to decrease the liquid level. Along with this, the molten metal M flows through the gap G1 and reaches the gap G2 as can be seen from FIG. 2. As a result, a head h is generated, and a pressure corresponding to the head h is applied to the molten metal M in the gutter main body 10 as illustrated in FIG. 2. Here, since impurities IM rise in the molten metal M and gather in the vicinity of the liquid surface, the molten metal M flowing through the gap G1 contains substantially no impurity IM. That is, molten metal M substantially containing no impurity IM exists in the gap G2. Thus, the liquid level of the molten metal M rises in the gap G2. Therefore, the substantially purified molten metal M flows over the outlet-side closed end plate 11 and flows into the mold 30 via the outflow auxiliary plate 7B. As a result, a high-quality product with less impurities IM can be obtained. In FIG. 2, h denotes a head of two liquid levels.
The above-described fact that application of the Lorentz force f can cause impurities IM in the molten metal M to rise in the molten metal M will be described below in detail.
The magnetic field strength in the molten metal M in FIG. 4 will be denoted by B. Here, as can be seen from FIGS. 7a and 7b , it is assumed that a Lorentz force f is generated downward. At this time, a force F that acts on a bottom portion of the gutter main body 10 is the sum of a force fg due to the gravity and a force fm due to the Lorentz force f, and is expressed as the following expression.
F=fg+fm
Here, since the horizontal area A of the gutter main body 10 is A=l×a (l: the length of the gutter main body 10, a: the width of the gutter main body 10), the pressure P at a bottom portion of the gutter main body 10 is expressed as the following expression.
P=F/A Furthermore, assuming here that the current density between the pair of electrodes 13 a and 13 b is constant, the Lorentz force f becomes zero at the surface of the molten metal, and I×B×l (N) at a bottom portion. Thus, the pressure is highest at a bottom portion. This state is illustrated in FIGS. 7a and 7 b.
Furthermore, the apparent density of the molten metal M affected by two influences of the Lorentz force f and the gravity is denoted by ρm, the density of mixed impurity particles is denoted by ρs, and the particle size is denoted by V. The buoyancy fa received from the molten metal M and the force fg due to the gravity simultaneously act on the impurity particles. At this time, assuming that the force received by the impurity particles is denoted by Fs, the following expression is satisfied.
$\begin{matrix} Fs = fa - fg \\ = ρ m \times V - ρ s \times V \\ = (ρ m - ρ s) \times V \end{matrix}$
Accordingly, the impurity particles move in the molten metal M as follows.
(a) ρm−ρs>0 Rise
(b) ρm−ρs<0 Settlement
(c) ρm−ρs=0 Floating
With the embodiment of the present invention described above, the following advantages can be obtained.
(1) Continuous purification of molten metal M is possible, which is consistent with a continuous casting method that has become a standard technology in the industry.
(2) Although the rise speed of impurities varies depending on the particle size, density, and the like of impurities, the residence time of the molten metal M in the gutter main body (sorting tank) may be increased by slowing down the flow speed or lengthening the gutter main body, for example, in the case of separating objects (having small particle size) having a low rise speed.
(3) Since the purification is neither physical nor mechanical, there is no need to replace a filter, which not only improves the work efficiency but also reduces costs.
(4) The specific gravity of the molten metal can be easily changed by changing the magnetic field strength or the current value, and an impurity removing operation can be performed according to the type of the molten metal M to be subjected to impurity removal.

Claims

1. A device for continuously removing impurities from molten metal, which sends electrically conductive molten metal to a metal product manufacturing device in a next stage, the device comprising:

a molten metal flow path body having a molten metal flow path for flowing electrically conductive molten metal that has flown from outside toward the metal product manufacturing device;

an inlet-side closed end plate and an outlet-side closed end plate that are provided in the molten metal flow path body so as to partition a front and a rear of the molten metal flow path and form an impurity removal space;

an electrode device composed of an inlet-side electrode and an outlet-side electrode that are provided in the impurity removal space, face each other in a longitudinal direction in which molten metal flows, and can be put into electrical contact with molten metal in the impurity removal space; and

a magnetic field device composed of a pair of permanent magnets that are provided outside the molten metal flow path forming body, face each other in a width direction intersecting the longitudinal direction, sandwich the impurity removal space of the molten metal flow path forming body in the width direction, have opposite poles facing each other, and can form a magnetic field in molten metal in the impurity removal space,

wherein the electrode device and the magnetic field device constitute an urging device that can apply a Lorentz force downward to molten metal in the impurity removal space so as to increase a density of the molten metal and cause impurities in the molten metal to rise up to a surface of the molten metal.

2. The device for continuously removing impurities from molten metal according to claim 1, wherein a power supply that can adjust an amount of current so as to adjust the Lorentz force is connected with the pair of electrodes in the electrode device.

3. The device for continuously removing impurities from molten metal according to claim 1, wherein the outlet-side closed end plate is configured to be capable of adjusting a mounting position in the molten metal flow path body in the longitudinal direction so as to adjust a length of the impurity removal space.

4. The device for continuously removing impurities from molten metal according to claim 1, wherein the outlet-side electrode is provided in a floating state in the impurity removal space so that a first gap opened vertically is formed between the outlet-side electrode and a bottom surface of the molten metal flow path forming body and a second gap opened in the longitudinal direction is formed between the outlet-side electrode and the outlet-side closed end plate.

5. The device for continuously removing impurities from molten metal according to claim 1, wherein the outlet-side closed end plate is configured such that a height of the outlet-side closed end plate can be adjusted so that an amount of molten metal that overflows can be adjusted.

6. The device for continuously removing impurities from molten metal according to claim 1, wherein a molten metal supply device that supplies molten metal to the molten metal flow path body and can adjust a supply amount is provided in a preceding stage of the molten metal flow path body.

7. A continuous impurity removal method for removing impurities from molten metal in sending electrically conductive molten metal to a metal product manufacturing device in a next stage, the method comprising:

preparing a molten metal flow path body having a molten metal flow path for flowing electrically conductive molten metal that has flown from outside toward the metal product manufacturing device;

providing an inlet-side closed end plate and an outlet-side closed end plate in the molten metal flow path body so as to partition a front and a rear of the molten metal flow path and form an impurity removal space;

providing, in the impurity removal space, an electrode device composed of an inlet-side electrode and an outlet-side electrode that face each other in a longitudinal direction in which molten metal flows and can be put into electrical contact with molten metal in the impurity removal space;

providing, outside the molten metal flow path forming body, a magnetic field device composed of a pair of permanent magnets that face each other in a width direction intersecting the longitudinal direction, sandwich the impurity removal space of the molten metal flow path forming body in the width direction, have opposite poles facing each other, and can form a magnetic field in molten metal in the impurity removal space; and

causing an urging device composed of the electrode device and the magnetic field device to apply a Lorentz force downward to molten metal in the impurity removal space so as to increase a density of the molten metal and cause impurities in the molten metal to rise up to a surface of the molten metal.

8. The method for continuously removing impurities from molten metal according to claim 7, further comprising adjusting an amount of current applied from a power supply to the pair of electrodes in the electrode device so as to adjust the Lorentz force.

9. The method for continuously removing impurities from molten metal according to claim 7, further comprising a step of adjusting a mounting position of the outlet-side closed end plate in the molten metal flow path body in the longitudinal direction so as to adjust a length of the impurity removal space.

10. The method for continuously removing impurities from molten metal according to claim 7, wherein the outlet-side electrode is provided in a floating state in the impurity removal space so that a first gap opened vertically is formed between the outlet-side electrode and a bottom surface of the molten metal flow path forming body and a second gap opened in the longitudinal direction is formed between the outlet-side electrode and the outlet-side closed end plate.

11. The method for continuously removing impurities from molten metal according to claim 7, wherein the outlet-side closed end plate is configured such that a height of the outlet-side closed end plate can be adjusted and an amount of molten metal that overflows can be adjusted.

12. The method for continuously removing impurities according to claim 7, wherein a molten metal supply device provided in a preceding stage of the molten metal flow path body adjusts an amount of molten metal supplied to the molten metal flow path body.

13. A device for continuously removing impurities from molten metal, which sends electrically conductive molten metal to a metal product manufacturing device in a next stage, the device comprising:

wherein the outlet-side electrode is provided in a floating state in the impurity removal space so that a first gap opened vertically is formed between the outlet-side electrode and a bottom surface of the molten metal flow path forming body and a second gap opened in the longitudinal direction is formed between the outlet-side electrode and the outlet-side closed end plate, and

the electrode device and the magnetic field device constitute an urging device that can apply a Lorentz force downward to molten metal in the impurity removal space so as to increase a density of the molten metal and cause impurities in the molten metal to rise up to a surface of the molten metal, and can send molten metal on an inner side than the outlet-side electrode in the impurity removal space through the first gap to the second gap.

14. A continuous impurity removal method for removing impurities from molten metal in sending electrically conductive molten metal to a metal product manufacturing device in a next stage, the method comprising:

providing, outside the molten metal flow path forming body, a magnetic field device composed of a pair of permanent magnets that face each other in a width direction intersecting the longitudinal direction, sandwich the impurity removal space of the molten metal flow path forming body in the width direction, have opposite poles facing each other, and can form a magnetic field in molten metal in the impurity removal space;

providing the outlet-side electrode in a floating state in the impurity removal space so that a first gap opened vertically is formed between the outlet-side electrode and a bottom surface of the molten metal flow path forming body and a second gap opened in the longitudinal direction is formed between the outlet-side electrode and the outlet-side closed end plate; and

causing an urging device composed of the electrode device and the magnetic field device to apply a Lorentz force downward to molten metal in the impurity removal space so as to increase a density of the molten metal and cause impurities in the molten metal to rise up to a surface of the molten metal, and send molten metal on an inner side than the outlet-side electrode through the first gap to the second gap.